Overview Information

Fennel is a perennial, pleasant-smelling herb with yellow flowers. It is native to the Mediterranean, but is now found throughout the world. Dried fennel seeds are often used in cooking as an anise-flavored spice. But don't confuse fennel with anise; though they look and taste similar, they are not the same. Fennel's dried ripe seeds and oil are used to make medicine.

Fennel is used by mouth for various digestive problems including heartburn, intestinal gas, bloating, loss of appetite, and colic in infants among othes. It is also used on the skin for excessive body hair growth in women, vaginal symptoms after menopause, and to prevent sunburn. But there is limited scientific evidence to support most of these uses.

In foods and beverages, fennel oil and fennel seed are used as flavoring agents.

In other manufacturing processes, fennel oil is used as a flavoring agent in certain laxatives, and as a fragrance component in soaps and cosmetics.

How does it work?

Fennel might relax the colon and decrease respiratory tract secretions. Fennel also appears to contain an ingredient that may act like estrogen in the body.

Uses & Effectiveness?

Possibly Effective for

Colic in breast-fed infants. Giving fennel seed oil can relieve colic in infants 2-12 weeks old. Also, breast-fed infants with colic who are given a specific multi-ingredient product containing fennel, lemon balm, and German chamomile seem to cry for a shorter period of time than other infants with colic. In addition, giving a specific tea containing fennel, chamomile, vervain, licorice, and balm-mint can reduce colic severity in infants.

Insufficient Evidence for

Painful menstruation (dysmenorrhea). Taking fennel extract four times daily starting at the beginning of a period can reduce pain in girls and young women with painful menstruation called dysmenorrhea. However, other research shows conflicting results.

Side Effects & Safety

Fennel is LIKELY SAFE when taken by mouth in the amounts commonly found in food. It is POSSIBLY SAFE when used as at appropriate doses for a short period of time. Fennel creams are also POSSIBLY SAFE when applied to the skin. There is not enough evidence to know whether fennel is safe when used as medicine for longer periods of time. Although rare, other side effects might include stomach and intestinal upset. Seizures related to taking fennel essential oil by mouth have also been reported.

Some people can have allergic skin reactions to fennel. People who are allergic to plants such as celery, carrot, and mugwort are more likely to also be allergic to fennel. Fennel can also make skin extra sensitive to sunlight and make it easier to get a sunburn. Wear sunblock if you are light-skinned.

Special Precautions & Warnings:

Pregnancy and breast-feeding: Not enough is known about the safety of using fennel during pregnancy. It's best to avoid use.

During breast-feeding, fennel is POSSIBLY UNSAFE. It's been reported that two breast-feeding infants experienced damage to their nervous systems after their mothers drank an herbal tea that contained fennel.

Children: Fennel products are POSSIBLY SAFE when used at appropriate doses by young infants for colic for up to one week.

Allergy to celery, carrot or mugwort: Fennel might cause an allergic reaction in people who are sensitive to these plants.

Hormone-sensitive condition such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids: Fennel might act like estrogen. If you have any condition that might be made worse by exposure to estrogen, do not use fennel.

Interactions?

Moderate Interaction

Be cautious with this combination

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Birth control pills (Contraceptive drugs) interacts with FENNEL

Some birth control pills contain estrogen. Fennel might have some of the same effects as estrogen. But fennel isn't as strong as the estrogen in birth control pills. Taking fennel along with birth control pills might decrease the effectiveness of birth control pills. If you take birth control pills along with fennel, use an additional form of birth control such as a condom.<br/><br/>
Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

Ciprofloxacin (Cipro) interacts with FENNEL

Ciprofloxacin (Cipro) is an antibiotic. Fennel might decrease how much ciprofloxacin (Cipro) the body absorbs. Taking fennel along with ciprofloxacin (Cipro) might decrease the effectiveness of ciprofloxacin (Cipro). To avoid this interaction take fennel at least one hour after ciprofloxacin (Cipro).

Estrogens interacts with FENNEL

Large amounts of fennel might have some of the same effects as estrogen. But fennel isn't as strong as estrogen pills. Taking fennel along with estrogen pills might decrease the effects of estrogen pills.<br/><br/>
Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

Tamoxifen (Nolvadex) interacts with FENNEL

Some types of cancer are affected by hormones in the body. Estrogen-sensitive cancers are cancers that are affected by estrogen levels in the body. Tamoxifen (Nolvadex) is used to help treat and prevent these types of cancer. Fennel seems to also affect estrogen levels in the body. Taking fennel along with tamoxifen might decrease the effectiveness of tamoxifen (Nolvadex). Do not take fennel if you are taking tamoxifen (Nolvadex).

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CONDITIONS OF USE AND IMPORTANT INFORMATION:
This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.